Discontinuous reception wakeup techniques

ABSTRACT

Methods, systems, and devices for wireless communications are described in which a user equipment (UE) may wake up from a sleep mode of a discontinuous reception (DRX) cycle based on receipt of uplink data. The UE may determine if an elapsed time between a prior receipt of one or more reference signals and an uplink transmission to the base station after waking up from the sleep mode is less than a threshold time value. If the elapsed time is less than the threshold time value, the UE may transmit an uplink transmission associated with the received uplink data prior to receiving one or more reference signals that may be used to update transmission parameters for uplink transmissions. If the elapsed time is at or above the threshold value, the UE may wait to receive the one or more reference signals and update the transmission parameters prior to the uplink transmission.

CROSS REFERENCE

The present Application for Patent claims the benefit of U.S.Provisional Patent Application No. 62/877,429 by MEYLAN et al., entitled“DISCONTINUOUS RECEPTION WAKEUP TECHNIQUES,” filed Jul. 23, 2019,assigned to the assignee hereof, and expressly incorporated by referenceherein.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to discontinuous reception (DRX) wakeup techniques.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM).

A wireless multiple-access communications system may include a number ofbase stations or network access nodes, each simultaneously supportingcommunication for multiple communication devices, which may be otherwiseknown as user equipment (UE). Some wireless communications systems maysupport UEs operating in a DRX mode. UEs in a DRX mode may transitionbetween a sleep state for power conservation and an active state fordata transmission and reception (during an ON-duration) according to aDRX configuration.

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support discontinuous reception (DRX) wakeuptechniques. In accordance with various aspects, a user equipment (UE)may wake up from a sleep mode of a DRX cycle based on receipt of uplinkdata, and initiate a transmission to a base station prior to a scheduledON duration of the DRX cycle and in some cases prior to receiving one ormore reference signals after transitioning out of the sleep mode. Insome cases, the UE may determine if an elapsed time between a priorreceipt of one or more reference signals and the transmission to thebase station after waking up from the sleep mode is less than athreshold time value. If the elapsed time is less than the thresholdvalue, the UE may transmit an uplink transmission associated with thereceived uplink data (e.g., a scheduling request or a random accesschannel (RACH) request message) prior to receiving one or more referencesignals that may be used to update transmission parameters for uplinktransmissions. If the elapsed time is at or above the threshold value,the UE waits to receive the one or more reference signals and update thetransmission parameters prior to the uplink transmission.

A method of wireless communications at a UE is described. The method mayinclude determining a first set of parameters for wirelesscommunications with a base station based on a first reference signal,transitioning into a sleep mode of a DRX cycle, where the DRX cycleincludes an ON-duration during which the UE is to wake up from the sleepmode to monitor for transmissions from the base station, and where theUE transitions to the sleep mode after the ON-duration, identifying,while in the sleep mode, that uplink data is present for transmissionfrom the UE, and transmitting a request to the base station for uplinkresources for transmission of the uplink data, where the request istransmitted before receiving a subsequent reference signal.

An apparatus for wireless communications at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to determine a firstset of parameters for wireless communications with a base station basedon a first reference signal, transition into a sleep mode of a DRXcycle, where the DRX cycle includes an ON-duration during which the UEis to wake up from the sleep mode to monitor for transmissions from thebase station, and where the UE transitions to the sleep mode after theON-duration, identify, while in the sleep mode, that uplink data ispresent for transmission from the UE, and transmit a request to the basestation for uplink resources for transmission of the uplink data, wherethe request is transmitted before receiving a subsequent referencesignal.

Another apparatus for wireless communications at a UE is described. Theapparatus may include means for determining a first set of parametersfor wireless communications with a base station based on a firstreference signal, transitioning into a sleep mode of a DRX cycle, wherethe DRX cycle includes an ON-duration during which the UE is to wake upfrom the sleep mode to monitor for transmissions from the base station,and where the UE transitions to the sleep mode after the ON-duration,identifying, while in the sleep mode, that uplink data is present fortransmission from the UE, and transmitting a request to the base stationfor uplink resources for transmission of the uplink data, where therequest is transmitted before receiving a subsequent reference signal.

A non-transitory computer-readable medium storing code for wirelesscommunications at a UE is described. The code may include instructionsexecutable by a processor to determine a first set of parameters forwireless communications with a base station based on a first referencesignal, transition into a sleep mode of a DRX cycle, where the DRX cycleincludes an ON-duration during which the UE is to wake up from the sleepmode to monitor for transmissions from the base station, and where theUE transitions to the sleep mode after the ON-duration, identify, whilein the sleep mode, that uplink data is present for transmission from theUE, and transmit a request to the base station for uplink resources fortransmission of the uplink data, where the request is transmitted beforereceiving a subsequent reference signal.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for monitoring, aftertransmitting the request to the base station, for the subsequentreference signal, and determining a second set of parameters forwireless communications with the base station based on the subsequentreference signal. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for receiving, fromthe base station, an uplink grant for the transmission of the uplinkdata, and transmitting at least a portion of the uplink data to the basestation based on the uplink grant.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the first reference signaland the subsequent reference signal from the base station include one ormore of a synchronization signal or a tracking reference signal. Someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a firsttime associated with the first reference signal and a second timeassociated with the identifying, where the first reference signal andthe subsequent reference signal may be transmitted in synchronizationsignal block (SSB) transmissions or tracking reference signal (TRS)transmissions of the base station, and determining an elapsed timebetween the first time and the second time, where the elapsed time maybe measured from a receipt of an SSB or a TRS used to update the firstset of parameters.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, transmitting the request tothe base station includes transmitting the request based on the elapsedtime being less than a threshold value. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the threshold value may be based on the elapsed time. In someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the threshold value may bebased on one or more operating conditions of the UE. In some examples ofthe method, apparatuses, and non-transitory computer-readable mediumdescribed herein, the one or more UE operating conditions include atemperature of one or more communications components at the UE, a rateof change of one or more of the first set of parameters across two ormore tracking loops, a rate of change of a distance between the UE andthe base station, or any combinations thereof. Some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein may further include operations, features, means, orinstructions for determining a specified maximum timing error of afrequency tracking loop, and selecting the threshold value based on thespecified maximum timing error.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the request to the basestation may be transmitted using one or more of random access channelresources or physical uplink control channel resources allocated forscheduling request transmissions. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the first set of parameters include one or more timingparameters, gain control parameters, frequency tracking parameters,power parameters, or any combinations thereof. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the UE updates one or more tracking loops based on thefirst set of parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationsthat supports discontinuous reception (DRX) wakeup techniques inaccordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a portion of a wireless communicationssystem that supports DRX wakeup techniques in accordance with aspects ofthe present disclosure.

FIGS. 3A and 3B illustrate examples of uplink transmission timelinesthat support DRX wakeup techniques in accordance with aspects of thepresent disclosure.

FIG. 4 illustrates an example of a process flow that supports DRX wakeuptechniques in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a process flow that supports DRX wakeuptechniques in accordance with aspects of the present disclosure.

FIGS. 6 and 7 show block diagrams of devices that support DRX wakeuptechniques in accordance with aspects of the present disclosure.

FIG. 8 shows a block diagram of a communications manager that supportsDRX wakeup techniques in accordance with aspects of the presentdisclosure.

FIG. 9 shows a diagram of a system including a device that supports DRXwakeup techniques in accordance with aspects of the present disclosure.

FIGS. 10 and 11 show block diagrams of devices that support DRX wakeuptechniques in accordance with aspects of the present disclosure.

FIG. 12 shows a block diagram of a communications manager that supportsDRX wakeup techniques in accordance with aspects of the presentdisclosure.

FIG. 13 shows a diagram of a system including a device that supports DRXwakeup techniques in accordance with aspects of the present disclosure.

FIGS. 14 through 16 show flowcharts illustrating methods that supportDRX wakeup techniques in accordance with aspects of the presentdisclosure.

DETAILED DESCRIPTION

A wireless device, such as a user equipment (UE), may implement adiscontinuous reception (DRX) cycle (e.g., a connected mode DRX (C-DRX)mode) where the UE transitions between an active state (e.g., where theUE wakes up to determine if data is available for the UE) and a sleepstate (e.g., where the UE shuts down various hardware/processes toconserve power). Such DRX cycles may enable the efficient use of batterypower for reception of downlink transmissions. In some cases, a basestation and a UE may establish a radio resource control (RRC) connectionand the UE may enter a sleep state of the DRX cycle when not activelycommunicating with the base station. For example, during RRC connectionestablishment, a DRX configuration, including timing for one or moreDRX-On durations, may be configured in an RRC connection setup requestor an RRC connection reconfiguration request. Between successive DRX-ONdurations, the UE may transition to sleep mode where one or morecomponents of a radio frequency (RF) chain (e.g., a baseband receiverand associated amplifiers) may be powered down to help conserve power.The DRX configuration may determine how frequently the UE is scheduledto wake-up and be available for receiving downlink transmissions inaccordance with the configured DRX cycle durations. It is noted that invarious examples discussed herein, reference is made to the UEtransitioning between sleep and awake modes with the understanding thatsuch modes refer to sleep and awake modes for components of the RFchain, and that other components of the UE (e.g., an applicationsprocessor, user interface, etc.) may be active during such sleep andawake modes.

In some cases, in addition to the scheduled wakeup durations of the UEthat are configured in the DRX cycle, the UE may also wake up atunscheduled times in response to arrival of uplink data to betransmitted from the UE. For example, a UE may be in a sleep mode of aDRX cycle and, during the sleep mode, uplink data for transmission fromthe UE arrives in an uplink transmission buffer (e.g., when anapplication running at the UE generates uplink data to be transmittedfrom the UE). Such unscheduled wakeup procedures may be referred to insome cases as “rude” wake ups due to their arrival during a DRX sleepcycle rudely awakening the UE. In such cases, the UE may immediatelywake up and initiate a procedure to obtain uplink resources fortransmission of the uplink data. For example, the

UE may power on the RF components that were in sleep mode and transmit ascheduling request (SR) or a random access channel (RACH) request toobtain uplink resources to transmit the uplink data. The transmission ofthe SR or RACH request by the UE may provide an indication to the basestation that the UE is no longer in sleep mode and that the base stationcan schedule communications with the UE outside of the configured DRX-ONduration.

In some cases, one or more uplink transmission parameters of the UE maybecome out-of-date due to the UE being in sleep mode and not keepingsuch parameters updated. For example, one or more of an automatic gaincontrol (AGC) loop, a frequency tracking loop (FTL), or a power delayprofile (PDP) loop at a wireless modem of the UE may be periodicallyupdated based on one or more measurements made at the UE of one or morepilot signals or reference signals transmitted by the base station(e.g., a tracking reference signal (TRS), channel state informationreference signal (CSI-RS), synchronization signal (SS) in asynchronization signal block (SSB), etc.). In some cases, the UE mayupdate such uplink transmission parameters prior to the uplinktransmission to the base station, which may enhance the likelihood ofsuccessful reception of the uplink transmission at the base station, atthe cost of latency added while the UE performs the update to the uplinktransmission parameters.

In accordance with various aspects of the present disclosure, a UE maydetermine an elapsed time since a prior update of one or moretransmission parameters and may initiate an uplink SR or RACHtransmission prior to a subsequent update of the transmission parametersif the elapsed time is less than a threshold value. If the elapsed timemeets or exceeds the threshold value the UE may wait until the one ormore parameters are updated (e.g., wait for a subsequent referencesignal from the base station and associated measurement procedures toupdate the transmission parameters). Such techniques may allow a UE totransmit an SR or RACH request relatively quickly upon the arrival ofuplink data, and thus enhance UE performance by reducing latencyassociated with the uplink transmission. In some cases, the thresholdvalue may be set such that error in one or more tracking loops is likelyto be relatively small and thus provide a reliable uplink transmissionof the UE. Further, such techniques may allow for update of the one ormore transmission parameters in parallel with the SR or RACHtransmission, and thus the UE may update the uplink transmissionparameters prior to uplink data transmissions that may follow the SR or

RACH transmissions. Such techniques may thus provide a key performanceindicator (KPI) such as “mobile originated ping latency” that is arelatively low value compared to cases where a UE always waits to updatetransmission parameters prior to an uplink transmission. Such KPIperformance may indicate relatively efficient communications between theUE and base station while also providing relatively low powerconsumption at the UE.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various operations may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples.

Aspects of the disclosure are initially described in the context of awireless communications system. Example timelines and process flowsillustrating aspects of the discussed techniques are then described.Aspects of the disclosure are further illustrated by and described withreference to apparatus diagrams, system diagrams, and flowcharts thatrelate to DRX wakeup techniques.

FIG. 1 illustrates an example of a wireless communications system 100that supports DRX wakeup techniques in accordance with aspects of thepresent disclosure. The wireless communications system 100 includes basestations 105, UEs 115, and a core network 130. In some examples, thewireless communications system 100 may be a Long Term Evolution (LTE)network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a NewRadio (NR) network. In some cases, wireless communications system 100may support enhanced broadband communications, ultra-reliable (e.g.,mission critical) communications, low latency communications, orcommunications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples,half-duplex communications may be performed at a reduced peak rate.Other power conservation techniques for UEs 115 include entering a powersaving “deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In somecases, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriersoperating in a licensed band (e.g., LAA). Operations in unlicensedspectrum may include downlink transmissions, uplink transmissions,peer-to-peer transmissions, or a combination of these. Duplexing inunlicensed spectrum may be based on frequency division duplexing (FDD),time division duplexing (TDD), or a combination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer mayperform packet segmentation and reassembly to communicate over logicalchannels. A Medium Access Control (MAC) layer may perform priorityhandling and multiplexing of logical channels into transport channels.The MAC layer may also use hybrid automatic repeat request (HARQ) toprovide retransmission at the MAC layer to improve link efficiency. Inthe control plane, the Radio Resource Control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and a base station 105 or core network 130supporting radio bearers for user plane data. At the Physical layer,transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback is one technique of increasing the likelihood that data isreceived correctly over a communication link 125. HARQ may include acombination of error detection (e.g., using a cyclic redundancy check(CRC)), forward error correction (FEC), and retransmission (e.g.,automatic repeat request (ARQ)). HARQ may improve throughput at the MAClayer in poor radio conditions (e.g., signal-to-noise conditions). Insome cases, a wireless device may support same-slot HARQ feedback, wherethe device may provide HARQ feedback in a specific slot for datareceived in a previous symbol in the slot. In other cases, the devicemay provide HARQ feedback in a subsequent slot, or according to someother time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an evolved universal mobiletelecommunication system terrestrial radio access (E-UTRA) absoluteradio frequency channel number (EARFCN)), and may be positionedaccording to a channel raster for discovery by UEs 115. Carriers may bedownlink or uplink (e.g., in an FDD mode), or be configured to carrydownlink and uplink communications (e.g., in a TDD mode). In someexamples, signal waveforms transmitted over a carrier may be made up ofmultiple sub-carriers (e.g., using multi-carrier modulation (MCM)techniques such as orthogonal frequency division multiplexing (OFDM) ordiscrete Fourier transform spread OFDM (DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

In some cases, UEs 115 and base stations 105 may be configured with DRXcycles that allow one or more UEs 115 to transition to a power-savingsleep mode between ON durations of the DRX cycles. In some cases, a UE115 may wake up from sleep mode of a DRX cycle based on receipt ofuplink data, and initiate a transmission to a base station 105 prior toa scheduled ON duration of the DRX cycle and in some cases prior toupdating one or more transmission parameters after transitioning out ofthe sleep mode. In some cases, the UE 115 initiate the transmissionprior to updating the one or more transmission parameters if an elapsedtime since a prior update is less than a threshold time value. If theelapsed time is less than the threshold time value, the UE 115 maytransmit an uplink transmission associated with the received uplink data(e.g., an SR or RACH request message) prior to receiving one or morereference signals that may be used to update the transmissionparameters. If the elapsed time is at or above the threshold value, theUE 115 may wait to receive the one or more reference signals and updatethe transmission parameters prior to the uplink transmission.

FIG. 2 illustrates an example of a wireless communications system 200that supports DRX wakeup techniques in accordance with aspects of thepresent disclosure. In some examples, wireless communications system 200may implement aspects of wireless communications system 100. Forexample, the wireless communications system 200 may include a basestation 105-a and a UE 115-a, which may be examples of the correspondingdevices described with reference to FIG. 1. Some examples of thewireless communications system 200 may support DRX techniques forreduced power consumption at the UE 115-a.

The base station 105-a may provide a network coverage for UE 115-awithin geographic coverage area 110-a. In some examples, UE 115-a maysupport DRX operation for improved power efficiency. For example, a UE115-a may operate according to a DRX configuration in which the UE 115-amonitors for communications during periodic ON-durations, andtransitions to a low power sleep mode between the periodic ON-durations.The time period between the start of each ON-duration may be referred toas a cycle duration. Further, in some cases, DRX cycles may have anidentified starting location (e.g., at the start of an identified slotwithin a subframe), and a configurable ON-duration (e.g., 2 slots) thatstarts at an offset (e.g., 4 slots) relative to the identified startinglocation.

The base station 105-a may transmit downlink communications 205 to theUE 115-a, and the UE 115-a may transmit uplink communications 210 to thebase station 105-a. In some cases, as will be discussed in more detailwith respect to FIGS. 3 through 5, the base station 105-a and UE 115-a,when performing an RRC connection establishment or reestablishment, mayconfigure a DRX configuration in which the UE 115-a may transition to asleep mode between ON durations of the DRX cycle in order to reducepower consumption. In some cases, the UE 115-a may set one or moreuplink and/or downlink transmission parameters for communications withthe base station 105-a based on measurements that are made from one ormore periodic pilot signals 215 that are transmitted by the base station105-a (e.g., one or more TRS, CSI-RS, SSB transmissions, or combinationsthereof). For example, the UE 115-a may maintain one or more trackingloops associated with the one or more transmission or receptionparameters (e.g., one or more AGC, FTL, PDP loops, or combinationsthereof) that may be updated based on measurements of the one or moreperiodic pilot signals 215.

In some cases as discussed herein, the UE 115-a may receive uplink datathat is to be transmitted to the base station 105-a, such as in anuplink buffer of the UE 115-a. Upon receipt of the uplink data, the UE115-a may transmit an uplink request 220 to the base station 105-a, suchas an SR on a physical uplink control channel (PUCCH) or RACH request,to request uplink resources for transmission of the uplink data receivedin the uplink buffer of the UE 115-a. In some systems, such as in NRsystems, the periodic pilot signals 215 of the base station 105-a (e.g.,SSB/TRS transmissions) may be relatively scarce relative to pilots ofother systems (e.g., LTE pilot signals), such as once every 20 ms. Insuch cases, if the UE 115-a were to wait for a subsequent periodic pilotsignal 215 after arrival of uplink data in order to update itstransmission/reception parameters, the UE 115-a could wait for up to 20ms, and an average of 10 ms, which may add a significant amount oflatency to the timing of the associated uplink request 220. Thus, insuch cases, waiting for SSB or TRS in order to update the one or more UE115-a tracking loops can become a dominant factor in the duration of thewakeup process.

Thus, techniques as discussed herein may provide that the UE 115-a mayinitiate the transmission of the uplink request 220, and/ortransmission/reception of other physical channels, prior to receiving asubsequent periodic pilot signal 215 from the base station 105-a if anelapsed time since a prior tracking loop update is less than a thresholdtime value. If the elapsed time is at or above the threshold value, theUE 115-a may wait to receive the one or more periodic pilot signals 215and update the transmission parameters prior to the transmission of theuplink request 220.

FIGS. 3A and 3B illustrate examples of uplink transmission timelines 300and 350, respectively, that support DRX wakeup techniques in accordancewith aspects of the present disclosure. In some examples, uplinktransmission timeline 300 and 350 may implement aspects of wirelesscommunications system 100 or 200. In the example of FIG. 3A, a basestation (e.g., a base station 105 of FIG. 1 or 2) may transmit one ormore reference signals 305 according to a configuration for periodicreference signal transmissions. In this example, a first referencesignal 305-a and a second reference signal 305-b may be transmitted bythe base station.

A UE that may be operating according to a DRX configuration may monitorfor some or all of the periodic reference signals 305 and may update oneor more uplink or downlink transmission parameters based on measurementsof the periodic reference signals 305. In this example, the UE maymonitor for and measure the first reference signal 305-a and may thentransition to a sleep mode 310. The UE, in this example, may initiate atimer associated with the first reference signal 305-a, and a timethreshold 320 may be set against the timer, where if the UE determinesan uplink transmission is needed (e.g., due to receipt of uplink datafor transmission), the UE may initiate an uplink transmission prior toreceipt of the second reference signal 305-b, as is illustrated in FIG.3B. In the example of FIG. 3A, the UE does not receive uplink data to betransmitted, and may remain in the sleep mode 310 until the start of ONduration 325 that is established in the DRX configuration. The UE maythen monitor for a physical downlink control channel (PDCCH) downlinktransmission 315 during the ON duration 325 to determine if downlink oruplink resources are configured for the UE.

In the example of FIG. 3B, after the UE transitions to sleep mode 310,the UE may identify an uplink data arrival 355 or other need to accessuplink resources. For example, the UE may determine that data hasarrived in an uplink transmission buffer from an application processorthat is running at the UE or is otherwise connected to the UE. In thisexample, the uplink data arrival 355 may occur prior to the expirationof the time threshold 320, and the UE may transmit uplink transmission360, such as an SR (e.g., if a PUCCH is configured with SR resources) ora random access request (RAR) using identified RACH resources. Theuplink transmission 360 may be transmitted prior to receipt andmeasurement of the second reference signal 305-b based on the uplinkdata arrival 355 being prior to the expiration of the time threshold320. In other cases, the uplink data arrival 355 may occur afterexpiration of the time threshold 320, in which case the UE may wait toreceive and measure the second reference signal 305-b before the uplinktransmission 360. In some cases, the starting time of the uplinktransmission 360 may be compared to the time threshold 320 to determinewhether the UE is to wait for the second reference signal 305-b or not.In the example of FIG. 3B, the UE may then transition to an awake mode365 and may monitor for the second reference signal 305-b and performone or more update procedures based on the second reference signal305-b. The UE may, in the awake mode 365, monitor for PDCCH transmission315, which may occur in the prior scheduled ON duration 325, or mayoccur prior to the scheduled ON duration 325.

In some examples, the time threshold 320 may be a time value that isselected to provide a relatively reliable uplink transmission 360 anddownlink transmission 315. For example, the time threshold 320 may be apreconfigured time threshold (e.g., 320 ms) that is based on aworst-case timing drift due to temperature variation of UE components.In other cases, the time threshold 320 may be preconfigured to span acertain number of reference signal 305 transmissions (e.g., no more than6 or 8 reference signal transmissions). In other cases, the timethreshold 320 may be set based on conditions at the UE, such as based ona current temperature indicated by one or more components of the UE(e.g., a temperature indicated by an RF baseband processor, low noiseamplifier (LNA) component, antenna module, etc.). For example, a firsttime threshold (e.g., 400 ms) may be set if the current temperature isless than a predetermined value, and a second time threshold (e.g., 320ms) may be set if the current temperature is above the predeterminedvalue (e.g., due to a larger amount of timing drift at highertemperatures). Thus, if a time since a prior loop update is less thanthe time threshold 320, the UE may skip the loop update for any commonC-DRX configuration, and move directly to the uplink transmission 360.

Thus, the latency associated with the uplink transmission 360 may beimproved relative to cases where the UE would wait to make an uplinktransmission. For example, rather than waiting for an average of 10 msfor a SSB/TRS and then performing measurement and processing that mayadd additional time (e.g., an additional 5-7 ms to perform measurement,clock programming, firmware processing, and RF chain configuration), theUE may skip to the processing operations that may reduce latency, onaverage, by more than half relative to waiting for a subsequent SSB/TRS.As indicated herein, in some aspects, the time threshold 320 may beselected to provide a potential timing error that is relatively low andwithin requirements of the UE. Further, in a worst case a retransmissionof the uplink transmission 360 (and/or a downlink transmission) may berequired, which may still occur, on average, prior to receipt of thesecond reference signal 305-b, and thus still provide lower latency thanwaiting for the second reference signal 305-b prior to the SR/RARtransmission.

FIG. 4 illustrates an example of a process flow 400 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The process flow 400 may include a base station 105-b and a UE 115-b,which may be examples of the corresponding devices described withreference to FIGS. 1 through 3. In some examples, the process flow 400may implement aspects of the wireless communications systems 100 and200. For example, the base station 105-b and the UE 115-b may supportDRX operations as discussed herein.

In the following description of the process flow 400, the operationsbetween the base station 105-b and the UE 115-b may be transmitted in adifferent order than the exemplary order shown, or the operationsperformed by the base station 105-b and the UE 115-b may be performed indifferent orders or at different times. Certain operations may also beleft out of the process flow 400, or other operations may be added tothe process flow 400.

The process flow 400 may, in some examples, commence at 405 with thebase station 105-b establishing a connection with the UE 115-b (e.g.,performing a cell acquisition procedure, a random access procedure, anRRC connection procedure, an RRC configuration procedure).

At 410, the base station 105-b may determine a DRX configuration (e.g.,C-DRX configuration) for the UE 115-b. In some cases, the base station105-b may determine the DRX configuration to provide ON-durations at theUE 115-b that correspond with a determined traffic periodicity, whichmay reduce power consumption at the UE 115-b. At 415, the base station105-b may transmit DRX configuration information to the UE 115-b. Insome cases, the DRX configuration may be provided in RRC signaling. Insome cases, as part of the connection establishment, the UE 115-b mayindicate a capability for DRX configurations, and the base station 105-bmay enable this capability with the DRX configuration information.Additionally or alternatively, all or part of the DRX configurationinformation may be provided in downlink control information (DCI) or inone or more MAC-CEs.

At 420, the UE 115-b may determine the DRX configuration. In some cases,the UE 115-b may determine the DRX configuration based on RRC signalingfrom the base station 105-b. At 425, the base station 105-b may transmitperiodic reference signals (e.g., SSB, TRS, CSI-RS transmissions, orcombinations thereof), and the UE 115-b may monitor for one or more ofthe periodic reference signals. At 430, the UE 115-b may performreference signal measurements and update one or more tracking loops, andinitiate DRX procedures based on the DRX configuration. Such DRXprocedures may include the UE 115-b transitioning to a sleep modebetween ON-durations, and transitioning to an awake mode to monitor fordownlink transmissions from the base station 105-b during ON-durations.

At 435, the UE 115-b may detect an uplink data arrival. In some cases,the uplink data arrival may be indicated by the presence of data in anuplink transmit buffer of the UE 115-b. For example, an applicationrunning at an application processor associated with the UE 115-a, whilethe UE 115-b is in a DRX sleep mode, may generate uplink data that is tobe transmitted to the base station 105-b. The arrival of the uplink datamay cause the UE 115-b to transition out of the sleep mode and into anawake state for transmission of a request to obtain resources fortransmission of the uplink data and reception of downlink transmissions.

At 440, the UE 115-b may determine that a time threshold since the priorreference signal measurement or tracking loop update has not elapsed. Insome cases, such a determination may be made based on a timer that isstarted at each tracking loop update. In some cases, a time of a priorreference signal measurement or tracking loop update may be recorded andcompared to a subsequent time associated with the uplink data arrival orexpected transmission time of the uplink request to determine if thetime threshold has elapsed.

At 445, based on the determination that the time threshold has notelapsed, the UE 115-b may transmit an uplink request, such as an SR orRACH transmission, prior to monitoring for and measuring a subsequentreference signal transmission from the base station 105-b. In thisexample, at 450, the UE 115-b may perform one or more reference signalmeasurements and update one or more transmission parameters based ontracking loop updated, in parallel with the downlink reception anduplink transmission processes.

FIG. 5 illustrates an example of a process flow 500 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The process flow 500 may include a base station 105-c and a UE 115-c,which may be examples of the corresponding devices described withreference to FIGS. 1 through 4. In some examples, the process flow 500may implement aspects of the wireless communications systems 100 and200. For example, the base station 105-c and the UE 115-c may supportDRX operations as discussed herein.

In the following description of the process flow 500, the operationsbetween the base station 105-c and the UE 115-c may be transmitted in adifferent order than the exemplary order shown, or the operationsperformed by the base station 105-c and the UE 115-c may be performed indifferent orders or at different times. Certain operations may also beleft out of the process flow 500, or other operations may be added tothe process flow 500.

The process flow 500 may, in some examples, commence at 505 with thebase station 105-c establishing a connection with the UE 115-c (e.g.,performing a cell acquisition procedure, a random access procedure, anRRC connection procedure, an RRC configuration procedure).

At 510, the base station 105-c may determine a DRX configuration for theUE 115-c. In some cases, the base station 105-c may determine the DRXconfiguration to provide ON-durations at the UE 115-c that correspondwith the determined traffic periodicity, which may reduce powerconsumption at the UE 115-c. At 515, the base station 105-c may transmitDRX configuration information to the UE 115-c. In some cases, the DRXconfiguration may be provided in RRC signaling. In some cases, as partof the connection establishment, the UE 115-c may indicate a capabilityfor DRX configurations, and the base station 105-c may enable thiscapability with the DRX configuration information. Additionally oralternatively, all or part of the DRX configuration information may beprovided in DCI or in one or more MAC-CEs.

At 520, the UE 115-c may determine the DRX configuration. In some cases,the UE 115-c may determine the DRX configuration based on RRC signalingfrom the base station 105-c. At 525, the base station 105-c may transmitperiodic reference signals (e.g., SSB, TRS, CSI-RS transmissions, orcombinations thereof), and the UE 115-c may monitor for one or more ofthe periodic reference signals. At 530, the UE 115-c may performreference signal measurements and update one or more tracking loops, andinitiate DRX procedures based on the DRX configuration. Such DRXprocedures may include the UE 115-c transitioning to a sleep modebetween ON-durations, and transitioning to an awake mode to monitor fordownlink transmissions from the base station 105-c during ON-durations.

At 535, the UE 115-c may detect an uplink data arrival. In some cases,the uplink data arrival may be indicated by the presence of data in anuplink transmit buffer of the UE 115-c. For example, an applicationrunning at an application processor of the UE 115-a, while the UE 115-cis in a DRX sleep mode, may generate uplink data that is to betransmitted to the base station 105-c. The arrival of the uplink datamay cause the UE 115-c to transition out of the sleep mode and into anawake state for transmission of a request to obtain resources fortransmission of the uplink data.

At 540, the UE 115-c may determine that a time threshold since the priorreference signal measurement or tracking loop update has elapsed. Insome cases, such a determination may be made based on a timer that isstarted at each tracking loop update. In some cases, a time of a priorreference signal measurement or tracking loop update may be recorded andcompared to a subsequent time associated with the uplink data arrival orexpected transmission time of the uplink request to determine if thetime threshold has elapsed.

At 545, based on the determination that the time threshold has elapsed,the UE 115-c may wait for a best reference signal transmission from thebase station 105-c. At 550, the base station 105-c may transmit thesubsequent reference signal (e.g., SSB/TRS), which may be received atthe UE 115-c.

At 555, the UE 115-c may perform reference signal measurements anddetermine one or more uplink/downlink transmission/reception parametersbased on the reference signal measurements. At 560, the UE 115-c maytransmit an uplink request, such as an SR or RACH transmission to thebase station 105-c.

FIG. 6 shows a block diagram 600 of a device 605 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The device 605 may be an example of aspects of a UE 115 as describedherein. The device 605 may include a receiver 610, a communicationsmanager 615, and a transmitter 620. The device 605 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

The receiver 610 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to DRX wakeuptechniques, etc.). Information may be passed on to other components ofthe device 605. The receiver 610 may be an example of aspects of thetransceiver 920 described with reference to FIG. 9. The receiver 610 mayutilize a single antenna or a set of antennas.

The communications manager 615 may determine a first set of parametersfor wireless communications with a base station based on a firstreference signal. In some cases, the first reference signal may bereceived from the base station and may be associated with a first time.The communications manager 615 may transition into a sleep mode of a DRXcycle, where the DRX cycle includes an ON-duration during which the UEis to wake up from the sleep mode to monitor for transmissions from thebase station, and where the UE transitions to the sleep mode after theON-duration. In some examples, the communications manager 615 maytransition into the sleep mode after the first time. The communicationsmanager 615 may identify, while in the sleep mode, that uplink data ispresent for transmission from the UE. In some cases, the identifying maybe associated with a second time. In some examples, the communicationsmanager 615 may determine an elapsed time between the first time and thesecond time. The communications manager 615 may transmit a request tothe base station for uplink resources for transmission of the uplinkdata, where the request is transmitted before receiving a subsequentreference signal. In some cases, the communications manager 615 maytransmit the request based on the elapsed time being less than athreshold value. In some cases, the subsequent reference signal may bereceived from the base station. The communications manager 615 may be anexample of aspects of the communications manager 910 described herein.

The communications manager 615, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 615, or itssub-components may be executed by a general-purpose processor, a digitalsignal processor (DSP), an application-specific integrated circuit(ASIC), a field programmable gate array (FPGA) or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed in the present disclosure.

The actions performed by the communications manager 615 as describedherein may be implemented to realize one or more potential advantages.For example, transmitting a request to the base station for uplinkresources for transmission of the uplink data before receiving asubsequent reference signal may allow the UE to decrease latency ofcommunications between the UE and the base station. In some examples,transmitting the request to the base station before receiving thesubsequent reference signal may further potentially reduce powerconsumption by decreasing the time a UE waits before transmitting uplinkdata.

A processor of the device 605 (e.g., a processor controlling thereceiver 610, the communications manager 615, the transmitter 620, or acombination thereof) may reduce latency associated with transmittinguplink data by performing an unscheduled wakeup procedure. For example,by transmitting the request to the base station before receiving thesubsequent reference signal, the device 605 may reduce processingoverhead (e.g., time or some other overhead) associated withtransmitting uplink data. Additionally or alternatively, the processormay provide for relatively low power consumption at the UE (e.g., bydecreasing the time a UE waits before transmitting uplink data.

The communications manager 615, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 615, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 615, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 620 may transmit signals generated by other componentsof the device 605. In some examples, the transmitter 620 may becollocated with a receiver 610 in a transceiver module. For example, thetransmitter 620 may be an example of aspects of the transceiver 920described with reference to FIG. 9. The transmitter 620 may utilize asingle antenna or a set of antennas.

FIG. 7 shows a block diagram 700 of a device 705 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The device 705 may be an example of aspects of a device 605, or a UE 115as described herein. The device 705 may include a receiver 710, acommunications manager 715, and a transmitter 745. The device 705 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to DRX wakeuptechniques, etc.). Information may be passed on to other components ofthe device 705. The receiver 710 may be an example of aspects of thetransceiver 920 described with reference to FIG. 9. The receiver 710 mayutilize a single antenna or a set of antennas.

The communications manager 715 may be an example of aspects of thecommunications manager 615 as described herein. The communicationsmanager 715 may include a loop update manager 720, a DRX manager 725, anuplink data identification component 730, a DRX timer 735, and an uplinktransmission manager 740. The communications manager 715 may be anexample of aspects of the communications manager 910 described herein.

The loop update manager 720 may determine a first set of parameters forwireless communications with a base station based on a first referencesignal. In some cases, the first reference signal may be received fromthe base station and may be associated with a first time.

The DRX manager 725 may transition into a sleep mode of a DRX cycle,where the DRX cycle includes an ON-duration during which the UE is towake up from the sleep mode to monitor for transmissions from the basestation, and where the UE transitions to the sleep mode after theON-duration. In some cases, the DRX manager 725 may transition into thesleep mode after the first time.

The uplink data identification component 730 may identify, while in thesleep mode, that uplink data is present for transmission from the UE. Insome cases, the identifying may be associated with a second time.

The DRX timer 735 may determine an elapsed time between the first timeand the second time.

The uplink transmission manager 740 may transmit a request to the basestation for uplink resources for transmission of the uplink data, wherethe request is transmitted before receiving a subsequent referencesignal. In some cases, the uplink transmission manager 740 may transmitthe request based on the elapsed time being less than a threshold value.In some cases, the subsequent reference signal may be received from thebase station.

The transmitter 745 may transmit signals generated by other componentsof the device 705. In some examples, the transmitter 745 may becollocated with a receiver 710 in a transceiver module. For example, thetransmitter 745 may be an example of aspects of the transceiver 920described with reference to FIG. 9. The transmitter 745 may utilize asingle antenna or a set of antennas.

FIG. 8 shows a block diagram 800 of a communications manager 805 thatsupports DRX wakeup techniques in accordance with aspects of the presentdisclosure. The communications manager 805 may be an example of aspectsof a communications manager 615, a communications manager 715, or acommunications manager 910 described herein. The communications manager805 may include a loop update manager 810, a DRX manager 815, an uplinkdata identification component 820, a DRX timer 825, an uplinktransmission manager 830, and a reference signal manager 835. Each ofthese modules may communicate, directly or indirectly, with one another(e.g., via one or more buses).

The loop update manager 810 may determine a first set of parameters forwireless communications with a base station based on a first referencesignal. In some cases, the first reference signal may be received fromthe base station and may be associated with a first time. In someexamples, the loop update manager 810 may determine a second set ofparameters for wireless communications with the base station based on asubsequent reference signal received from the base station. In somecases, the first set of parameters includes one or more timingparameters, gain control parameters, frequency tracking parameters,power parameters, or any combinations thereof. In some cases, the UEupdates one or more tracking loops based on the first set of parameters.

The DRX manager 815 may transition into a sleep mode of a DRX cycle,where the DRX cycle includes an ON-duration during which the UE is towake up from the sleep mode to monitor for transmissions from the basestation, and where the UE transitions to the sleep mode after theON-duration. In some cases, the DRX manager 815 may transition into thesleep mode after the first time.

The uplink data identification component 820 may identify, while in thesleep mode, that uplink data is present for transmission from the UE. Insome cases, the identifying may be associated with a second time.

The DRX timer 825 may determine an elapsed time between the first timeand the second time. In some examples, the DRX timer 825 may determinethat the elapsed time exceeds or does not exceed the threshold value. Insome cases, the threshold value is a predetermined time value. In someexamples, the threshold value is based on the elapsed time. In somecases, the threshold value is based on one or more UE operatingconditions. In some cases, the one or more UE operating conditionsinclude a temperature of RF communications components at the UE, a rateof change of one or more of the first set of parameters across two ormore tracking loops, a rate of change of a distance between the UE andthe base station, or any combinations thereof. In some cases, thethreshold value is selected to provide a timing error of a frequencytracking loop that is within a specified maximum timing error. In someexamples, the DRX timer 825 may determine a maximum timing error of afrequency tracking loop and select the threshold value based on themaximum timing error.

The uplink transmission manager 830 may transmit, based on the elapsedtime being less than a threshold value, a request to the base stationfor uplink resources for transmission of the uplink data, where therequest is transmitted before receiving a subsequent reference signalfrom the base station. In some examples, the uplink transmission manager830 may transmit, based on the elapsed time exceeding the thresholdvalue, the request to the base station for uplink resources fortransmission of the uplink data after determining a second set ofparameters.

In some examples, the uplink transmission manager 830 may receive, fromthe base station, an uplink grant for the transmission of the uplinkdata. In some examples, the uplink transmission manager 830 may transmitat least a portion of the uplink data to the base station based on theuplink grant.

In some cases, the request to the base station is transmitted using oneor more of random access channel resources or physical uplink controlchannel resources allocated for scheduling request transmissions.

The reference signal manager 835 may monitor, before or aftertransmitting the request to the base station, for the subsequentreference signal from the base station. In some cases, the firstreference signal and the subsequent reference signal from the basestation include one or more of a synchronization signal or a trackingreference signal. In some cases, the first reference signal and thesubsequent reference signal are transmitted in synchronization signalblock (SSB) transmissions or tracking reference signal (TRS)transmissions of the base station, and where the elapsed time ismeasured from a receipt of a SSB or TRS used to update the first set ofparameters.

FIG. 9 shows a diagram of a system 900 including a device 905 thatsupports DRX wakeup techniques in accordance with aspects of the presentdisclosure. The device 905 may be an example of or include thecomponents of device 605, device 705, or a UE 115 as described herein.The device 905 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 910, an I/Ocontroller 915, a transceiver 920, an antenna 925, memory 930, and aprocessor 940. These components may be in electronic communication viaone or more buses (e.g., bus 945).

The communications manager 910 may determine a first set of parametersfor wireless communications with a base station based on a firstreference signal received from the base station that is associated witha first time, transition, after the first time, into a sleep mode of aDRX cycle, where the DRX cycle includes an ON-duration during which theUE is to wake up from the sleep mode to monitor for transmissions fromthe base station, and where the UE transitions to the sleep mode afterthe ON-duration, identify, while in the sleep mode, that uplink data ispresent for transmission from the UE, the identifying associated with asecond time, determine an elapsed time between the first time and thesecond time, and transmit, based on the elapsed time being less than athreshold value, a request to the base station for uplink resources fortransmission of the uplink data, where the request is transmitted beforereceiving a subsequent reference signal from the base station.

The I/O controller 915 may manage input and output signals for thedevice 905. The I/O controller 915 may also manage peripherals notintegrated into the device 905. In some cases, the I/O controller 915may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 915 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 915may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 915may be implemented as part of a processor. In some cases, a user mayinteract with the device 905 via the I/O controller 915 or via hardwarecomponents controlled by the I/O controller 915.

The transceiver 920 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 920 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 920may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas.

In some cases, the wireless device may include a single antenna 925.However, in some cases the device may have more than one antenna 925,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 930 may include RAM and ROM. The memory 930 may storecomputer-readable, computer-executable code 935 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 930 may contain, among otherthings, a basic input/output system (BIOS) which may control basichardware or software operation such as the interaction with peripheralcomponents or devices.

The processor 940 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 940 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 940. The processor 940 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 930) to cause the device 905 to perform variousfunctions (e.g., functions or tasks supporting DRX wakeup techniques).

The code 935 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 935 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 935 may not be directly executable by theprocessor 940 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 10 shows a block diagram 1000 of a device 1005 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The device 1005 may be an example of aspects of a base station 105 asdescribed herein. The device 1005 may include a receiver 1010, acommunications manager 1015, and a transmitter 1020. The device 1005 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to DRX wakeuptechniques, etc.). Information may be passed on to other components ofthe device 1005. The receiver 1010 may be an example of aspects of thetransceiver 1320 described with reference to FIG. 13. The receiver 1010may utilize a single antenna or a set of antennas.

The communications manager 1015 may configure a first UE with a DRXconfiguration that is based on a DRX cycle that includes an ON-durationduring which the UE is to wake up from a sleep mode to monitor fortransmissions from the base station, discontinue the DRX configurationof the first UE, and receive, prior to an expected ON-duration, anuplink transmission from the first UE that indicates the UE has uplinkdata for transmission. The communications manager 1015 may be an exampleof aspects of the communications manager 1310 described herein.

The communications manager 1015, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1015, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 1015, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1015, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1015, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The transmitter 1020 may transmit signals generated by other componentsof the device 1005. In some examples, the transmitter 1020 may becollocated with a receiver 1010 in a transceiver module. For example,the transmitter 1020 may be an example of aspects of the transceiver1320 described with reference to FIG. 13. The transmitter 1020 mayutilize a single antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a device 1105 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The device 1105 may be an example of aspects of a device 1005, or a basestation 105 as described herein. The device 1105 may include a receiver1110, a communications manager 1115, and a transmitter 1130. The device1105 may also include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1110 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to DRX wakeuptechniques, etc.). Information may be passed on to other components ofthe device 1105. The receiver 1110 may be an example of aspects of thetransceiver 1320 described with reference to FIG. 13. The receiver 1110may utilize a single antenna or a set of antennas.

The communications manager 1115 may be an example of aspects of thecommunications manager 1015 as described herein. The communicationsmanager 1115 may include a DRX manager 1120 and an uplink transmissionmanager 1125. The communications manager 1115 may be an example ofaspects of the communications manager 1310 described herein.

The DRX manager 1120 may configure a first UE with a DRX configurationthat is based on a DRX cycle that includes an ON-duration during whichthe UE is to wake up from a sleep mode to monitor for transmissions fromthe base station and discontinue the DRX configuration of the first UE.

The uplink transmission manager 1125 may receive, prior to an expectedON-duration, an uplink transmission from the first UE that indicates theUE has uplink data for transmission.

The transmitter 1130 may transmit signals generated by other componentsof the device 1105. In some examples, the transmitter 1130 may becollocated with a receiver 1110 in a transceiver module. For example,the transmitter 1130 may be an example of aspects of the transceiver1320 described with reference to FIG. 13. The transmitter 1130 mayutilize a single antenna or a set of antennas.

FIG. 12 shows a block diagram 1200 of a communications manager 1205 thatsupports DRX wakeup techniques in accordance with aspects of the presentdisclosure. The communications manager 1205 may be an example of aspectsof a communications manager 1015, a communications manager 1115, or acommunications manager 1310 described herein. The communications manager1205 may include a DRX manager 1210 and an uplink transmission manager1215. Each of these modules may communicate, directly or indirectly,with one another (e.g., via one or more buses).

The DRX manager 1210 may configure a first UE with a DRX configurationthat is based on a DRX cycle that includes an ON-duration during whichthe UE is to wake up from a sleep mode to monitor for transmissions fromthe base station. In some examples, the DRX manager 1210 may discontinuethe DRX configuration of the first UE. The uplink transmission manager1215 may receive, prior to an expected ON-duration, an uplinktransmission from the first UE that indicates the UE has uplink data fortransmission.

FIG. 13 shows a diagram of a system 1300 including a device 1305 thatsupports DRX wakeup techniques in accordance with aspects of the presentdisclosure. The device 1305 may be an example of or include thecomponents of device 1005, device 1105, or a base station 105 asdescribed herein. The device 1305 may include components forbi-directional voice and data communications including components fortransmitting and receiving communications, including a communicationsmanager 1310, a network communications manager 1315, a transceiver 1320,an antenna 1325, memory 1330, a processor 1340, and an inter-stationcommunications manager 1345. These components may be in electroniccommunication via one or more buses (e.g., bus 1350).

The communications manager 1310 may configure a first UE with a DRXconfiguration that is based on a DRX cycle that includes an ON-durationduring which the UE is to wake up from a sleep mode to monitor fortransmissions from the base station, discontinue the DRX configurationof the first UE, and receive, prior to an expected ON-duration, anuplink transmission from the first UE that indicates the UE has uplinkdata for transmission.

The network communications manager 1315 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1315 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1320 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1320 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1320 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1325.However, in some cases the device may have more than one antenna 1325,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1330 may include RAM, ROM, or a combination thereof. Thememory 1330 may store computer-readable code 1335 including instructionsthat, when executed by a processor (e.g., the processor 1340) cause thedevice to perform various functions described herein. In some cases, thememory 1330 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1340 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1340 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1340. The processor 1340 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1330) to cause the device 1305 to perform various functions(e.g., functions or tasks supporting DRX wakeup techniques).

The inter-station communications manager 1345 may manage communicationswith other base station 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1345 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1345 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1335 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1335 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1335 may not be directly executable by theprocessor 1340 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 14 shows a flowchart illustrating a method 1400 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The operations of method 1400 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1400 may be performed by a communications manager as described withreference to FIGS. 6 through 9. In some examples, a UE may execute a setof instructions to control the functional elements of the UE to performthe functions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1405, the UE may determine a first set of parameters for wirelesscommunications with a base station based on a first reference signal.The operations of 1405 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1405may be performed by a loop update manager as described with reference toFIGS. 6 through 9.

At 1410, the UE may transition into a sleep mode of a DRX cycle, wherethe DRX cycle includes an ON-duration during which the UE is to wake upfrom the sleep mode to monitor for transmissions from the base station,and where the UE transitions to the sleep mode after the ON-duration.The operations of 1410 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1410may be performed by a DRX manager as described with reference to FIGS. 6through 9.

At 1415, the UE may identify, while in the sleep mode, that uplink datais present for transmission from the UE. The operations of 1415 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1415 may be performed by an uplink dataidentification component as described with reference to FIGS. 6 through9.

At 1420, the UE may transmit a request to the base station for uplinkresources for transmission of the uplink data, where the request istransmitted before receiving a subsequent reference signal. Theoperations of 1420 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1420 may beperformed by an uplink transmission manager as described with referenceto FIGS. 6 through 9.

FIG. 15 shows a flowchart illustrating a method 1500 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The operations of method 1500 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1500 may be performed by a communications manager as described withreference to FIGS. 6 through 9. In some examples, a UE may execute a setof instructions to control the functional elements of the UE to performthe functions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1505, the UE may determine a first set of parameters for wirelesscommunications with a base station based on a first reference signal.The operations of 1505 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1505may be performed by a loop update manager as described with reference toFIGS. 6 through 9.

At 1510, the UE may transition into a sleep mode of a DRX cycle, wherethe DRX cycle includes an ON-duration during which the UE is to wake upfrom the sleep mode to monitor for transmissions from the base station,and where the UE transitions to the sleep mode after the ON-duration.The operations of 1510 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1510may be performed by a DRX manager as described with reference to FIGS. 6through 9.

At 1515, the UE may identify, while in the sleep mode, that uplink datais present for transmission from the UE. The operations of 1515 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1515 may be performed by an uplink dataidentification component as described with reference to FIGS. 6 through9.

At 1520, the UE may transmit a request to the base station for uplinkresources for transmission of the uplink data, where the request istransmitted before receiving a subsequent reference signal. Theoperations of 1520 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1520 may beperformed by an uplink transmission manager as described with referenceto FIGS. 6 through 9.

At 1525, the UE may monitor, after transmitting the request to the basestation, for the subsequent reference signal. The operations of 1525 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1525 may be performed by areference signal manager as described with reference to FIGS. 6 through9.

At 1530, the UE may determine a second set of parameters for wirelesscommunications with the base station based on the subsequent referencesignal. The operations of 1530 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1530may be performed by a loop update manager as described with reference toFIGS. 6 through 9.

At 1535, the UE may receive, from the base station, an uplink grant forthe transmission of the uplink data. The operations of 1535 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1535 may be performed by an uplinktransmission manager as described with reference to FIGS. 6 through 9.

At 1540, the UE may transmit at least a portion of the uplink data tothe base station based on the uplink grant. The operations of 1540 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1540 may be performed by anuplink transmission manager as described with reference to FIGS. 6through 9.

FIG. 16 shows a flowchart illustrating a method 1600 that supports DRXwakeup techniques in accordance with aspects of the present disclosure.The operations of method 1600 may be implemented by a UE 115 or itscomponents as described herein. For example, the operations of method1600 may be performed by a communications manager as described withreference to FIGS. 6 through 9. In some examples, a UE may execute a setof instructions to control the functional elements of the UE to performthe functions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1605, the UE may determine a first set of parameters for wirelesscommunications with a base station based on a first reference signal.The operations of 1605 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1605may be performed by a loop update manager as described with reference toFIGS. 6 through 9.

At 1610, the UE may transition into a sleep mode of a DRX cycle, wherethe DRX cycle includes an ON-duration during which the UE is to wake upfrom the sleep mode to monitor for transmissions from the base station,and where the UE transitions to the sleep mode after the ON-duration.The operations of 1610 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1610may be performed by a DRX manager as described with reference to FIGS. 6through 9.

At 1615, the UE may identify, while in the sleep mode, that uplink datais present for transmission from the UE. The operations of 1615 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1615 may be performed by an uplink dataidentification component as described with reference to FIGS. 6 through9.

At 1620, the UE may determine a first time associated with the firstreference signal and a second time associated with the identifying. Theoperations of 1620 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1620 may beperformed by a DRX timer as described with reference to FIGS. 6 through9.

At 1625, the UE may determine an elapsed time between the first time andthe second time that exceeds a threshold value. The operations of 1625may be performed according to the methods described herein. In someexamples, aspects of the operations of 1625 may be performed by a DRXtimer as described with reference to FIGS. 6 through 9.

At 1630, the UE may monitor for a subsequent reference signal. Theoperations of 1630 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1630 may beperformed by a reference signal manager as described with reference toFIGS. 6 through 9.

At 1635, the UE may determine a second set of parameters for wirelesscommunications with the base station based on the subsequent referencesignal. The operations of 1635 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1635may be performed by a loop update manager as described with reference toFIGS. 6 through 9.

At 1640, the UE may transmit, based on the elapsed time exceeding thethreshold value, the request to the base station for uplink resourcesfor transmission of the uplink data after determining the second set ofparameters. The operations of 1640 may be performed according to themethods described herein. In some examples, aspects of the operations of1640 may be performed by an uplink transmission manager as describedwith reference to FIGS. 6 through 9.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned herein as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell maybe associated with a lower-powered base station, as compared with amacro cell, and a small cell may operate in the same or different (e.g.,licensed, unlicensed, etc.) frequency bands as macro cells. Small cellsmay include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEshaving an association with the femto cell (e.g., UEs in a closedsubscriber group (CSG), UEs for users in the home, and the like). An eNBfor a macro cell may be referred to as a macro eNB. An eNB for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. An eNB may support one or multiple (e.g., two, three, four,and the like) cells, and may also support communications using one ormultiple component carriers.

The wireless communications systems described herein may supportsynchronous or asynchronous operation. For synchronous operation, thebase stations may have similar frame timing, and transmissions fromdifferent base stations may be approximately aligned in time. Forasynchronous operation, the base stations may have different frametiming, and transmissions from different base stations may not bealigned in time. The techniques described herein may be used for eithersynchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other non-transitory medium that can be used tocarry or store desired program code means in the form of instructions ordata structures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include CD, laser disc, optical disc,digital versatile disc (DVD), floppy disk and Blu-ray disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communications at a userequipment (UE), comprising: determining a first set of parameters forwireless communications with a base station based at least in part on afirst reference signal; transitioning into a sleep mode of adiscontinuous reception cycle, wherein the discontinuous reception cycleincludes an ON-duration during which the UE is to wake up from the sleepmode to monitor for transmissions from the base station, and wherein theUE transitions to the sleep mode after the ON-duration; identifying,while in the sleep mode, that uplink data is present for transmissionfrom the UE; and transmitting a request to the base station for uplinkresources for transmission of the uplink data, wherein the request istransmitted before receiving a subsequent reference signal.
 2. Themethod of claim 1, further comprising: monitoring, after transmittingthe request to the base station, for the subsequent reference signal;and determining a second set of parameters for wireless communicationswith the base station based at least in part on the subsequent referencesignal.
 3. The method of claim 1, further comprising: receiving, fromthe base station, an uplink grant for the transmission of the uplinkdata; and transmitting at least a portion of the uplink data to the basestation based at least in part on the uplink grant.
 4. The method ofclaim 1, wherein the first reference signal and the subsequent referencesignal include one or more of a synchronization signal or a trackingreference signal.
 5. The method of claim 4, further comprising:determining a first time associated with the first reference signal anda second time associated with the identifying, wherein the firstreference signal and the subsequent reference signal are transmitted insynchronization signal block (SSB) transmissions or tracking referencesignal (TRS) transmissions of the base station; and determining anelapsed time between the first time and the second time, wherein theelapsed time is measured from a receipt of an SSB or a TRS used toupdate the first set of parameters.
 6. The method of claim 5, whereintransmitting the request to the base station further comprises:transmitting the request based at least in part on the elapsed timebeing less than a threshold value.
 7. The method of claim 6, wherein thethreshold value is based at least in part on the elapsed time.
 8. Themethod of claim 6, wherein the threshold value is based at least in parton one or more operating conditions of the UE.
 9. The method of claim 8,wherein the one or more UE operating conditions include a temperature ofone or more communications components at the UE, a rate of change of oneor more of the first set of parameters across two or more trackingloops, a rate of change of a distance between the UE and the basestation, or any combinations thereof.
 10. The method of claim 6, furthercomprising: determining a specified maximum timing error of a frequencytracking loop; and selecting the threshold value based on the specifiedmaximum timing error.
 11. The method of claim 1, wherein the request tothe base station is transmitted using one or more of random accesschannel resources or physical uplink control channel resources allocatedfor scheduling request transmissions.
 12. The method of claim 1, whereinthe first set of parameters include one or more timing parameters, gaincontrol parameters, frequency tracking parameters, power parameters, orany combinations thereof.
 13. The method of claim 12, wherein the UEupdates one or more tracking loops based at least in part on the firstset of parameters.
 14. An apparatus for wireless communications at auser equipment (UE), comprising: a processor, memory coupled with theprocessor; and instructions stored in the memory and executable by theprocessor to cause the apparatus to: determine a first set of parametersfor wireless communications with a base station based at least in parton a first reference signal; transition into a sleep mode of adiscontinuous reception cycle, wherein the discontinuous reception cycleincludes an ON-duration during which the UE is to wake up from the sleepmode to monitor for transmissions from the base station, and wherein theUE transitions to the sleep mode after the ON-duration; identify, whilein the sleep mode, that uplink data is present for transmission from theUE; and transmit a request to the base station for uplink resources fortransmission of the uplink data, wherein the request is transmittedbefore receiving a subsequent reference signal.
 15. The apparatus ofclaim 14, wherein the instructions are further executable by theprocessor to cause the apparatus to: monitor, after transmitting therequest to the base station, for the subsequent reference signal; anddetermine a second set of parameters for wireless communications withthe base station based at least in part on the subsequent referencesignal.
 16. The apparatus of claim 14, wherein the instructions arefurther executable by the processor to cause the apparatus to: receive,from the base station, an uplink grant for the transmission of theuplink data; and transmit at least a portion of the uplink data to thebase station based at least in part on the uplink grant.
 17. Theapparatus of claim 14, wherein the first reference signal and thesubsequent reference signal include one or more of a synchronizationsignal or a tracking reference signal.
 18. The apparatus of claim 17wherein the instructions are further executable by the processor tocause the apparatus to: determine a first time associated with the firstreference signal and a second time associated with the identifying,wherein the first reference signal and the subsequent reference signalare transmitted in synchronization signal block (SSB) transmissions ortracking reference signal (TRS) transmissions of the base station; anddetermine an elapsed time between the first time and the second time,wherein the elapsed time is measured from a receipt of an SSB or TRSused to update the first set of parameters.
 19. The apparatus of claim18, wherein the instructions are further executable by the processor tocause the apparatus to: transmit the request based at least in part onthe elapsed time being less than a threshold value.
 20. The apparatus ofclaim 19, wherein the threshold value is based at least in part on theelapsed time.
 21. The apparatus of claim 19, wherein the threshold valueis based at least in part on one or more operating conditions of the UE.22. The apparatus of claim 21, wherein the one or more UE operatingconditions include a temperature of one or more communicationscomponents at the UE, a rate of change of one or more of the first setof parameters across two or more tracking loops, a rate of change of adistance between the UE and the base station, or any combinationsthereof.
 23. The apparatus of claim 19, wherein the instructions arefurther executable by the processor to cause the apparatus to: determinea specified maximum timing error of a frequency tracking loop; andselect the threshold value based on the specified maximum timing error.24. The apparatus of claim 14, wherein the request to the base stationis transmitted using one or more of random access channel resources orphysical uplink control channel resources allocated for schedulingrequest transmissions.
 25. The apparatus of claim 14, wherein the firstset of parameters include one or more timing parameters, gain controlparameters, frequency tracking parameters, power parameters, or anycombinations thereof.
 26. The apparatus of claim 21, wherein the UEupdates one or more tracking loops based at least in part on the firstset of parameters.
 27. An apparatus for wireless communications at auser equipment (UE), comprising: means for determining a first set ofparameters for wireless communications with a base station based atleast in part on a first reference signal; means for transitioning intoa sleep mode of a discontinuous reception cycle, wherein thediscontinuous reception cycle includes an ON-duration during which theUE is to wake up from the sleep mode to monitor for transmissions fromthe base station, and wherein the UE transitions to the sleep mode afterthe ON-duration; means for identifying, while in the sleep mode, thatuplink data is present for transmission from the UE; and means fortransmitting a request to the base station for uplink resources fortransmission of the uplink data, wherein the request is transmittedbefore receiving a subsequent reference signal.
 28. The apparatus ofclaim 27, further comprising: means for monitoring, after transmittingthe request to the base station, for the subsequent reference signalfrom the base station; and means for determining a second set ofparameters for wireless communications with the base station based atleast in part on the subsequent reference signal from the base station.29. The apparatus of claim 27, further comprising: means for receiving,from the base station, an uplink grant for the transmission of theuplink data; and means for transmitting at least a portion of the uplinkdata to the base station based at least in part on the uplink grant. 30.A non-transitory computer-readable medium storing code for wirelesscommunications at a user equipment (UE), the code comprisinginstructions executable by a processor to: determine a first set ofparameters for wireless communications with a base station based atleast in part on a first reference signal; transition into a sleep modeof a discontinuous reception cycle, wherein the discontinuous receptioncycle includes an ON-duration during which the UE is to wake up from thesleep mode to monitor for transmissions from the base station, andwherein the UE transitions to the sleep mode after the ON-duration;identify, while in the sleep mode, that uplink data is present fortransmission from the UE; and transmit a request to the base station foruplink resources for transmission of the uplink data, wherein therequest is transmitted before receiving a subsequent reference signal.